What company can I order the services of developing an application for the bank. Please advise a good company. With fast enough development speed.

I can recommend you a company that we ourselves have asked for services from. We ordered the development of a financial application for our company. You can contact owlab, they develop a lot of fintech applications. You can order banking app development here. They have a huge number of already developed applications in this direction. So you won't have any problems developing your app.